The present invention is related to the structure of a terminal to be soldered in mounting a switch used for various kinds of electronic devices on a circuit board. In particular, the present invention is related to the terminal structure of a push switch.
A push switch used for various kinds of small-sized electronic devices such as a mobile phone is disclosed in a patent document 1, for example.
An example of the push switch of the related art is shown in FIG. 13. This push switch 100 includes a switch case 111, a first fixed electrode 112, a pair of second fixed electrodes 113, a movable electrode 114 and a cover sheet 115.
The switch case 111 has a box-type shape which upper surface is opened, and is formed by insulative resin. The first fixed electrode 112 is fixed at the center portion of the inner bottom surface of the opening portion. The pair of second fixed electrodes 113 are respectively fixed at opposed positions of the switch case so as to sandwich the first fixed electrode 112 therebetween.
The movable electrode 114 includes a dome-shaped center portion 114A expanded upward and is accommodated within the switch case 111 so that the lower surface of the center portion 114A opposes to the first fixed electrode 112 with a space therebetween and an edge portion 114B of the movable electrode contacts with the second fixed electrodes 113.
The cover sheet 115 is formed by a flexible insulative film having a square-shape and is attached on the upper surface of the switch case 111 so as to cover the opening portion of the switch case 111.
When the cover sheet 115 is pushed down from the upper direction, the center portion 114A of the movable electrode 114 located beneath the cover sheet is pushed down via the cover sheet 115. When the pushed-down force exceeds a predetermined value, the center portion 114A is reversed moderately to expand downward, whereby the lower surface of the center portion 114A contacts with the first fixed electrode 112. Thus, the first fixed electrode 112 conducts with the second fixed electrodes 113 via the movable electrode 114 (switch on state). In contrast, when the pushed-down force is removed, the center portion 114A returns moderately to the original position to expand upward due to the restoring force of the movable electrode 114, whereby the conductive state between the first fixed electrode 112 and the second fixed electrodes 113 is cancelled (switch off state).
As shown in FIG. 14, the tip ends of extended portions from the first fixed electrode 112 and each of the second fixed electrodes 113 are bent upward to form terminal portions 112A and 113A, respectively. These terminal portions are exposed to the outer side surface 111A of the switch case 111 and used as external connection terminals.
[Patent Document 1] Japanese Patent No. 4457918